FIELD OF THE INVENTION
The invention relates to a filter plug including a pin bar connector body being composed of plastic and having a chamber being open towards at least one side, a number of parallel plug pins being disposed in a grid, entering the chamber from a rear side of the chamber through a base and emerging on the open side of the chamber, and at least one filter element, preferably a ferrite body, having holes formed therein matching the grid of the plug pins, being plugged onto the plug pins, and being held in the chamber without any play in axial direction of the plug pins, by means of at least one spring element being integrally formed on the pin bar body and composed of plastic. Such a filter plug is disclosed in German Petty Patent G 90 05 597.7.
In the case of such filter plugs, the ferrite bodies, which are plugged onto the plug pins together with bushing capacitors, are used for decoupling electromagnetic interference.
In order to be able to position the ferrite bodies, which have relatively large production-dependent tolerances, in the correct orientation and without play and to attach them securely, it is known and usual to bond the ferrite bodies into the pin bar body of the plug. However, that requires laborious manufacturing steps, wherein the curing of the adhesive in particular is linked with a time loss in mass production. In addition, in the case of some plastics which are used for pin bar bodies of a plug, bonded connections are not possible.
German Petty Patent G 89 12 173.2 discloses a filter plug having tubular ferrite bodies which are pressed against the base of a chamber by means of a plastic retaining strip. The retaining strip has pegs which are integrally formed in the grid of the plug pins, the ferrite bodies are plugged onto them and the chamber base is constructed with attachments which are in the form of truncated cones and are opposite the pegs. The retaining strip is constructed as a separate component and is attached to the pin bar body by means of lateral latching hooks and placed into recesses of the pin bar body.
In the case of the filter plug which is disclosed in German Petty Patent G 90 05 597.7, spring elements are provided which are integrally formed on the chamber base of the pin bar body, wherein a ferrite core which is plugged onto the plug pins and is inserted into the chamber is pressed into the chamber and held firmly there, against the force of the spring element, by means of a screening housing which is latched-in on the pin bar body. The ferrite core is thus not fixed in the final position on the shielding housing by means of an additional component, until the chamber has been closed.